Segmented solid feed pump

ABSTRACT

A system is provided with a segmented solid feed pump having a plurality of pump segments disposed along a closed-loop path. The plurality of pump segments are coupled together in series along the closed-loop path, and the plurality of pump segments move along the closed-loop path. Furthermore, each pump segment includes a holding receptacle.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to a pump for a solid, suchas particulate matter. More particularly, the pump may be used fordelivering solid feedstock (e.g., coal) to a gasifier in an integratedgasification combined cycle (IGCC) power plant.

A typical pump designed for solids, such as particulate matter, has asingle continuous channel. For example, the pump may rotate a diskwithin a circular housing, thereby driving the particulate matter alonga circular path from an inlet to an outlet. Unfortunately, the outlet isabruptly angled relative to the circular path, thereby causing potentialclogging, high stresses, and high power requirements in the pump.Moreover, the pump is limited to a circular path.

BRIEF DESCRIPTION OF THE INVENTION

Certain embodiments commensurate in scope with the originally claimedinvention are summarized below. These embodiments are not intended tolimit the scope of the claimed invention, but rather these embodimentsare intended only to provide a brief summary of possible forms of theinvention. Indeed, the invention may encompass a variety of forms thatmay be similar to or different from the embodiments set forth below.

In a first embodiment, a system includes a segmented solid feed pumphaving a closed-loop path and a plurality of pump segments coupledtogether in series along the closed-loop path. In addition, each pumpsegment has a holding receptacle, and the plurality of pump segmentsmove along the closed-loop path.

In a second embodiment, a system includes a segmented solid feed pumphaving a closed-loop path and a plurality of pump segments coupledtogether in series along the closed-loop path, wherein the plurality ofpump segments move along the closed-loop path. In addition, thesegmented solid feed pump includes a first material transport sectiondisposed in a first fixed position along a first portion of theclosed-loop path. The first material transport section includes a firstinlet duct, a first outlet duct, and a first guide extending between thefirst inlet duct and the first outlet duct.

In a third embodiment, a system includes a segmented solid feed pumphaving a closed-loop path and a plurality of pump segments coupledtogether in series along the closed-loop path, wherein the plurality ofpump segments move along the closed-loop path. In addition, each pumpsegment has opposite side walls, an open top, and a movable bottom wall.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 a schematic block diagram of an embodiment of an integratedgasification combined cycle (IGCC) power plant utilizing a segmentedsolid feed pump;

FIG. 2 is a schematic side view of an embodiment of a segmented solidfeed pump oriented in a vertical arrangement;

FIG. 3 is a schematic side view of an embodiment of a segmented solidfeed pump oriented in another vertical arrangement;

FIG. 4 is a schematic top view of an embodiment of a segmented solidfeed pump oriented in a horizontal arrangement;

FIG. 5 is a schematic side view of an embodiment of the segmented solidfeed pump as illustrated in FIG. 4;

FIG. 6 is a schematic side view of three adjacent pump segments of asegmented solid feed pump in accordance with certain embodiments;

FIG. 7 is a schematic side view of an embodiment of a pump segment of asegmented solid feed pump as illustrated in FIGS. 1-6;

FIG. 8 is a schematic top view of an embodiment of the pump segment asillustrated in FIG. 7;

FIG. 9 is a schematic front end cross-sectional view of an embodiment ofthe pump segment as illustrated in FIG. 7, taken along line 9-9;

FIG. 10 is a schematic rear end cross-sectional view of an embodiment ofthe pump segment as illustrated in FIG. 7, taken along line 10-10;

FIG. 11 is a schematic cross-sectional view of the segmented solid feedpump taken along line 11-11 of FIG. 5;

FIG. 12 is a schematic cross-sectional view of the segmented solid feedpump taken along line 12-12 of FIG. 5;

FIG. 13 is a schematic cross-sectional view of the segmented solid feedpump taken along line 13-13 of FIG. 5;

FIG. 14 is a schematic cross-section view of the segmented solid feedpump taken along line 14-14 of FIG. 5;

FIG. 15 is a partial schematic side view of an embodiment of a segmentedsolid feed pump having pump segments with movable bottom walls;

FIG. 16 is a partial schematic side view of another embodiment of asegmented solid feed pump having pump segments with movable bottomwalls;

FIG. 17 is a partial schematic side view of another embodiment of asegmented solid feed pump having pump segments with movable bottomwalls;

FIG. 18 is a schematic side view of an embodiment of independent guidetracks of the segmented solid feed pump of FIG. 17; and

FIG. 19 is a schematic side view of an embodiment of a segmented solidfeed pump having a material transport section along an inwardly curvedportion of a closed-loop path.

DETAILED DESCRIPTION OF THE INVENTION

One or more specific embodiments of the present invention will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.

FIG. 1 is a diagram of an embodiment of an integrated gasificationcombined cycle (IGCC) system 100 utilizing one or more segmented solidfeed pumps 10. For example, in certain embodiments, the disclosed solidfeed pumps 10 may be posimetric pumps. The term “posimetric” may bedefined as capable of metering (e.g., measuring an amount of) andpositively displacing (e.g., trapping and forcing displacement of) asubstance being delivered by the pump 10. As discussed in detail below,embodiments of the segmented solid feed pump 10 may include a pluralityof pump segments interlinked together along a closed-loop pump path.Each pump segment is able to meter and positively displace a definedvolume of a substance, such as a solid fuel feedstock. The pump path maybe oriented in a vertical arrangement, a horizontal arrangement, or anyarrangement between vertical and horizontal arrangements. Furthermore,the pump path may have a circular shape or a non-circular shape. Forexample, the pump path may have a racetrack shape with opposite parallelportions between opposite curved portions. By further example, the pumppath may have an oval shape. Each pump segment may have a receptacle,such as a cup-shaped receptacle, configured to hold a solid substance.Each pump segment also may include opposite ends that overlap withadjacent pump segments, thereby blocking leakage of the substance beingpumped. Although the segmented solid feed pump 10 is discussed withreference to the IGCC system 100 in FIG. 1, the disclosed embodiments ofthe segmented solid feed pump 10 may be used in any suitableapplication.

The IGCC system 100 produces and burns a synthetic gas, i.e., syngas, togenerate electricity. Elements of the IGCC system 100 may include asolid fuel source 102 that may be utilized as a source of energy for theIGCC. The solid fuel source 102 may include coal, petroleum coke,biomass, wood-based materials, agricultural wastes, or other carboncontaining solids items. The solid fuel source 102 may be passed to afeedstock preparation unit 104. The feedstock preparation unit 104 may,for example, resize or reshaped the fuel source 102 by chopping,milling, shredding, pulverizing, briquetting, or pelletizing the solidfuel source 102 to generate feedstock. The feedstock also may be driedor at least partially dried. Alternatively, the moisture or liquidcontent of the feedstock may be increased to the extent that themoisture or liquid content does not preclude the ability of thefeedstock to enter, lockup, and exit the pump.

In the illustrated embodiment, the segmented solid feed pump 10 deliversthe feedstock from the feedstock preparation unit 104 to a gasifier 106.As discussed in detail below, the segmented solid feed pump 10 isconfigured to meter and pressurize the feedstock received by thefeedstock preparation unit 104 from the solid fuel source 102.Alternatively, after metering or pressurization, the feedstock fromfeedstock preparation unit 104 may be combined with a carrier gas, suchas nitrogen from the DGAN compressor 124, as described below, tofacilitate transport of the feedstock to the gasifier 106. In otherembodiments, compatible gases from other sources, such as CO₂ from gascleaning unit 110, may be used to facilitate the transport of the solidfeedstock to gasifier 106.

The gasifier 106 may convert the feedstock into a syngas, e.g., acombination of carbon monoxide and hydrogen. This conversion may beaccomplished by subjecting the feedstock to a controlled amount of steamand oxygen at elevated pressures, e.g., from approximately 20 bar to 85bar, and temperatures, e.g., approximately 700 degrees Celsius to 1600degrees Celsius, depending on the type of gasifier 106 utilized in thesystem 100. The gasification process may include the feedstockundergoing a pyrolysis process, whereby the feedstock is heated.Temperatures inside the gasifier 106 may range from approximately 150degrees Celsius to 700 degrees Celsius during the pyrolysis process,depending on the fuel source 102 utilized to generate the feedstock. Theheating of the feedstock during the pyrolysis process may generate asolid, (e.g., char), and residue gases, (e.g., carbon monoxide,hydrogen, and nitrogen). The char remaining from the feedstock from thepyrolysis process may only weigh up to approximately 30% of the weightof the original feedstock.

A combustion process may then occur in the gasifier 106. The combustionmay include introducing oxygen to the char and residue gases. The charand residue gases may react with the oxygen to form carbon dioxide andcarbon monoxide, which provides heat for the subsequent gasificationreactions. The temperatures during the combustion process may range fromapproximately 700 degrees Celsius to 1600 degrees Celsius. Next, steammay be introduced into the gasifier 106 during a gasification step. Thechar may react with the carbon dioxide and steam to produce carbonmonoxide and hydrogen at temperatures ranging from approximately 800degrees Celsius to 1100 degrees Celsius. In essence, the gasifierutilizes steam and oxygen to allow some of the feedstock to be “burned”to produce carbon dioxide and release energy, which drives a secondreaction that converts further feedstock to hydrogen and additionalcarbon monoxide.

In this way, a resultant gas is manufactured by the gasifier 106. Thisresultant gas may, for example, include approximately 85% of carbonmonoxide and hydrogen in equal proportions, as well as CO₂, H₂O, CH₄,HCl, HF, COS, NH₃, HCN, and H₂S. This resultant gas may be termed dirtysyngas, since it contains, for example, H₂S. The gasifier 106 may alsogenerate solid byproducts, such as slag 108, which may be a wet ashmaterial. This slag 108 may be removed from the gasifier 106 anddisposed of, for example, as road base or as another building material.To clean the dirty syngas, a gas cleaning unit 110 may be utilized. Thegas cleaning unit 110 may scrub the dirty syngas to remove the HCl, HF,COS, HCN, and H₂S from the dirty syngas, which may include separation ofsulfur 111 in a sulfur processor 112 by, for example, an acid gasremoval process in the sulfur processor 112. Furthermore, sulfurprocessor 112 also may include conversion of the sulfur enteringprocessor 112 into a sulfur containing byproduct, such as elementalsulfur or sulfuric acid. Moreover, the gas cleaning unit 110 mayseparate salts 113 from the dirty syngas via a water treatment unit 114that may utilize water purification techniques to generate usable salts113 from the dirty syngas. Subsequently, the gas from the gas cleaningunit 110 may include clean syngas, (e.g., the sulfur 111 has beenremoved from the syngas), with trace amounts of other chemicals, e.g.,NH₃ (ammonia) and CH₄ (methane).

A gas processor 116 may be utilized to remove residual gas components117 from the clean syngas such as, ammonia and methane, as well asmethanol or any residual chemicals, or to react a portion of the cleansyngas carbon monoxide with water to produce carbon dioxide andhydrogen. However, removal of residual gas components 117 from the cleansyngas or reaction of the clean syngas with water is optional, since theclean syngas may be utilized as a fuel even when containing the residualgas components 117, e.g., tail gas. In certain embodiments, the cleansyngas may include approximately 3% CO, approximately 55% H₂, andapproximately 40% CO₂ and is substantially stripped of H₂S. This cleansyngas may be transmitted to a combustor 120, e.g., a combustionchamber, of a gas turbine engine 118 as combustible fuel. Alternatively,the reaction of CO with water may be carried out in or upstream of gascleaning unit 110. Further, alternatively, CO₂ may be removed from theclean syngas prior to transmission to the gas turbine engine. In otherembodiments, a compressor may be used to first compress the syngas tohigher pressure before feeding the syngas to combustor 120.

The IGCC system 100 may further include an air separation unit (ASU)122. The ASU 122 may operate to separate air into component gases by,for example, distillation techniques. The ASU 122 may separate oxygenfrom the air supplied to it from a supplemental air compressor 123, andthe ASU 122 may transfer the separated oxygen to the gasifier 106.Additionally the ASU 122 may transmit separated nitrogen to a diluentnitrogen (DGAN) compressor 124.

The DGAN compressor 124 may compress the nitrogen received from the ASU122 at least to pressure levels equal to those in the combustor 120, soas not to interfere with the proper combustion of the syngas. Thus, oncethe DGAN compressor 124 has adequately compressed the nitrogen to aproper level, the DGAN compressor 124 may transmit the compressednitrogen to the combustor 120 of the gas turbine engine 118. Thenitrogen may be used as a diluent to facilitate control of emissions,for example. In other embodiments, after additional compression (asappropriate), the nitrogen also may be used as a carrier gas tofacilitate transport of the solid feedstock to the gasifier 106.

As described previously, the compressed nitrogen may be transmitted fromthe DGAN compressor 124 to the combustor 120 of the gas turbine engine118. The gas turbine engine 118 may include a turbine 130, a drive shaft131 and a compressor 132, as well as the combustor 120. The combustor120 may receive fuel, such as syngas, which may be injected underpressure from fuel nozzles. This fuel may be mixed with compressed airas well as compressed nitrogen from the DGAN compressor 124, andcombusted within combustor 120. This combustion may create hotpressurized exhaust gases.

The combustor 120 may direct the exhaust gases towards an exhaust inletof the turbine 130. As the exhaust gases from the combustor 120 passthrough the turbine 130, the exhaust gases force turbine blades in theturbine 130 to rotate the drive shaft 131 along an axis of the gasturbine engine 118. As illustrated, the drive shaft 131 is connected tovarious components of the gas turbine engine 118, including thecompressor 132.

The drive shaft 131 may connect the turbine 130 to the compressor 132 toform a rotor. The compressor 132 may include blades coupled to the driveshaft 131. Thus, rotation of turbine blades in the turbine 130 may causethe drive shaft 131 connecting the turbine 130 to the compressor 132 torotate blades within the compressor 132. This rotation of blades in thecompressor 132 causes the compressor 132 to compress air received via anair intake in the compressor 132. The compressed air may then be fed tothe combustor 120 and mixed with fuel and compressed nitrogen to allowfor higher efficiency combustion. Drive shaft 131 may also be connectedto load 134, which may be a stationary load, such as an electricalgenerator for producing electrical power, for example, in a power plant.Indeed, load 134 may be any suitable device that is powered by therotational output of the gas turbine engine 118.

The IGCC system 100 also may include a steam turbine engine 136. Thesteam turbine engine 136 may drive a second load 140. The second load140 may also be an electrical generator for generating electrical power.However, both the first and second loads 134, 140 may be other types ofloads capable of being driven by the gas turbine engine 118 and steamturbine engine 136. In addition, although the gas turbine engine 118 andsteam turbine engine 136 may drive separate loads 134 and 140, as shownin the illustrated embodiment, the gas turbine engine 118 and steamturbine engine 136 may also be utilized in tandem to drive a single loadvia a single shaft. The specific configuration of the steam turbineengine 136, as well as the gas turbine engine 118, may beimplementation-specific and may include any combination of sections.

The system 100 may also include a heat recovery steam generator HRSG138. Heated exhaust gas from the gas turbine engine 118 may betransported into the HRSG 138 and used to heat water and produce steamused to power the steam turbine engine 136. Exhaust from, for example, alow-pressure section of the steam turbine engine 136 may be directedinto a condenser 142. The condenser 142 may utilize a cooling tower 128to exchange heated water for chilled water. The cooling tower 128 actsto provide cool water to the condenser 142 to aid in condensing thesteam transmitted to the condenser 142 from the steam turbine engine136. Condensate from the condenser 142 may, in turn, be directed intothe HRSG 138. Again, exhaust from the gas turbine engine 118 may also bedirected into the HRSG 138 to heat the water from the condenser 142 andproduce steam.

In combined cycle systems such as IGCC system 100, hot exhaust may flowfrom the gas turbine engine 118 and pass to the HRSG 138, where it maybe used to generate high-pressure, high-temperature steam. The steamproduced by the HRSG 138 may then be passed through the steam turbineengine 136 for power generation. In addition, the produced steam mayalso be supplied to any other processes where steam may be used, such asto the gasifier 106. The gas turbine engine 118 generation cycle isoften referred to as the “topping cycle,” whereas the steam turbineengine 136 generation cycle is often referred to as the “bottomingcycle.” By combining these two cycles as illustrated in FIG. 1, the IGCCsystem 100 may lead to greater efficiencies in both cycles. Inparticular, exhaust heat from the topping cycle may be captured and usedto generate steam for use in the bottoming cycle.

FIG. 2 is a schematic side view of an embodiment of the segmented solidfeed pump 10 oriented in a vertical arrangement. As indicated by thelegend, cross 12 indicates a horizontal X-axis or direction out of thepage, arrow 14 indicates a horizontal Y-axis or direction parallel tothe page, and arrow 16 indicates a vertical Z-axis or direction parallelto the page. In the illustrated embodiment, the segmented solid feedpump 10 includes a material transport section 200 disposed along aportion of a segmented pump loop or carriage loop 202. As discussed indetail below, the material transport section 200 is generally fixed inposition, while the carriage loop 202 moves relative to the materialtransport section 200. The loop 202 includes a plurality of pumpsegments 204 coupled together one after another in series about aclosed-loop path 206. Each pump segment 204 includes a carriage 208having a holding receptacle 210 defined by a bottom wall 212, an opentop 214, opposite side walls 216, a front coupling 218, and a rearcoupling 220. In the illustrated embodiment, each pump segment 204orients the open top 214 outwardly away from the closed-loop path 206.As discussed further below, each carriage 208 at least partially matesin an overlapping connection with adjacent carriages 208 on oppositefront and rear sides in the transport section 200 of pump 10. Forexample, each carriage 208 has the front coupling 218 at least partiallyoverlapping with the rear coupling 220 of a frontward carriage 208,while the carriage 208 has the rear coupling 220 at least partiallyoverlapping with the front coupling 218 of a rearward carriage 208facilitating the temporary joining or engagement of adjacent carriages208 in transport section 200. In this manner, the carriages 208 are atleast partially overlapping with adjacent carriages 208 about at least aportion of the closed-loop path 206. For example, as discussed in detailbelow, adjacent carriages 208 may at least partially overlap one anotherbetween an inlet duct 240 and an outlet duct 248 of the closed-loop path206, while the adjacent carriages 208 may or may not overlap one anotherin other portions of the closed-loop path 206. In certain embodiments,the adjacent carriages 208 may interlock with one another alongoverlapping portions to define a substantially rigid channel between theinlet duct 240 and the outlet duct 248. In addition, each carriage 208includes one or more track followers or wheels 222.

The illustrated closed-loop path 206 includes a track structure 224engaged with the track followers or wheels 222 of each carriage 208. Forexample, embodiments of the track structure 224 may include a chain, abelt, a rail, or any suitable stationary or movable structure. In oneembodiment, the track followers or wheels 222 may be rotatable orpivotable linkages fixed to the track structure 224, while the trackstructure 224 moves along the closed-loop path 206. In anotherembodiment, the track structure 224 may be fixed along the closed-looppath 206, while the track followers or wheels 222 are driven to movealong the closed-loop path 206. In still another embodiment, the trackstructure 224 may be a gear or belt drive system that may includeelements such as guides and tensioners. The closed-loop path 206 mayhave a variety of shapes, such as a circular shape or a non-circularshape. In the illustrated embodiment, the closed-loop path 206 has aracetrack shape, which includes opposite straight path portions 226 and228 disposed between opposite curved path portions 230 and 232. Forexample, the straight path portion 226 may extend along the transportsection 200 between the inlet duct 240 and the outlet duct 248, whereinthe straight path portion 226 may extend at least proximate to orslightly upstream of the inlet duct 240 and at least proximate to orslightly downstream of the outlet duct 248. In other embodiments, theclosed-loop path 206 may be oval or substantially curved. For example,the portion 226 may be a curved path portion extending along thetransport section 200 between the inlet duct 240 and the outlet duct248. Furthermore, the curved path portion may have a substantiallyconstant arc that extends at least proximate to or slightly upstream ofthe inlet duct 240 and at least proximate to or slightly downstream ofthe outlet duct 248.

In the illustrated embodiment, the segmented solid feed pump 10 isoriented in a vertical arrangement. In particular, the illustratedclosed-loop path 206 may be oriented in a vertical plane relative to thevertical axis 16. In the illustrated vertical orientation of thecarriage loop 202, the straight path portion 226 is an upper portion,while the straight path portion 228 is a lower portion vertically offsetbelow the upper portion. Furthermore, the illustrated material transportsection 200 is coupled to the upper straight path portion 226. Theillustrated straight path portions 226 and 228 are generally parallelwith one another, although other embodiments may orient the straightpath portions 226 and 228 in a non-parallel arrangement. The oppositecurved path portions 230 and 232 have opposite C-shapes, although othercurved shapes may be employed in alternative embodiments. In theillustrated embodiment, the open top 214 of each carriage 208 facesupwardly along the upper portion 226, downwardly along the lower portion228, leftwardly along the left curved path portion 230, and rightwardlyalong the right curved path portion 232.

The illustrated material transport section 200 includes an inlet ormetering zone 234, an outlet or pressurization zone 236, and anintermediate metering and/or lock-up zone 238. In the illustratedembodiment, the inlet or metering zone 234 includes an inlet duct 240having an inlet 242, an outlet 244, and a closed wall 246 between theinlet and the outlet 244. The closed wall 246 may include an inner wallportion 245 and an outer wall portion 247, wherein the inner wallportion 245 extends into an interior of the carriages 208 while theouter wall portion 247 extends around an exterior of the carriages 208.For example, the inner wall portion 245 may extend to the bottom of thepassing carriages 208 at an angle to guide flow of a substance into thecarriages 208, while also blocking any back flow of the substance. Theoutlet or pressurization zone 236 includes an outlet duct 248 having aninlet 250, an outlet 252, and a closed wall 254 between the inlet 250and the outlet 252. The closed wall 254 may include an inner wallportion 253 and an outer wall portion 255, wherein the inner wallportion 253 extends into an interior of the carriages 208 while theouter wall portion 255 extends around an exterior of the carriages 208.For example, the inner wall portion 253 may extend to the bottom of thepassing carriages 208 at an angle to guide flow of a substance out ofthe carriages 208, e.g., gradually scoop up and deliver the substancethrough the outlet duct 248. The lock-up zone 238 includes a contouredguide plate or cover 256 extending between the closed wall 246 of theinlet duct 240 and the closed wall 254 of the outlet duct 248. Forexample, the cover 256 may extend over the open tops 214 of thecarriages 208 moving between the outlet 244 of the inlet duct 240 andthe inlet 250 of the outlet duct 248. In this manner, the cover 256completely closes off the holding receptacle 210 of each carriage 208passing between the inlet duct 240 and the outlet duct 248.

In certain embodiments, the material transport section 200 may beconfigured to transport, meter, and pressurize the substance (e.g., asolid fuel feedstock) being handled by the segmented solid feed pump 10.For example, the inlet duct 240 of pump 10 may be configured tofacilitate the ready or free flow of substance through inlet duct 240into passing receptacles 210, such that pump 10 will not be starved ofthe substance. In certain embodiments, the flow of substance throughinlet duct 240 may be mechanically assisted, such as by mechanicalvibration, where care is taken to ensure the vibration does notinterfere with achieving lockup in lockup zone 238. Furthermore, incertain embodiments, the flow of substance through inlet duct 240 may bepneumatically assisted, such as by a pneumatic system, where care istaken to ensure that the substance effectively flows into receptacles210. Some embodiments also may employ other flow aiding elements tofacilitate the flow of substance through the inlet duct 240. In theillustrated embodiment, the substance thus may flow into inlet duct 240through the inlet 242 in an inlet direction 258, and then through theoutlet 244 into a passing carriage 208 in an outlet direction 260. Inthe illustrated embodiment, the holding receptacle 210 of each carriage208 has an equal and constant volume for metering purposes. Thus, avolume of pumped substance per unit of time can be easily calculatedbased on the number of carriages 208 passing by the outlet 244 of theinlet duct 240 per unit of time. Similarly, metering or control of thevolume of substance pumped per unit of time may be effected bymonitoring and adjusting the speed at which carriages 208 pass inlet240. In certain embodiments, the speed may be controlled by a drivemechanism, such as a motor with speed control. Thus, the speed controlcan be used to increase or decrease the flow rate of substance beingdelivered by the pump 10. In another embodiment, one or more sensors maybe disposed at one or more locations to track the number of carriage 208passing by a portion of the pump 10 per unit of time. For example, theinlet or metering zone 234 may include one or more sensors to track thenumber of carriages 208 passing by the outlet 244 of the inlet duct 240per unit of time. By further example, the sensors may be disposed at anylocation along the loop 202.

As illustrated, the inlet duct 240 delivers the substance to the passingcarriages 208 in directions 258 and 260. For example, the inletdirections 258 and 260 may be parallel to the vertical axis 16 andperpendicular to a carriage direction 268 of the passing carriages 208moving along the upper straight path portion 226. As the substance fillseach holding receptacle 210, each carriage 208 moves from the inlet duct240 toward the cover 256 of the lock-up zone 238. The cover 256 extendsover the open top 314 of each carriage 208 between the inlet duct 240and the outlet duct 248. Furthermore, the cover 256 may be shaped toprovide a smooth transition between the outlet 244 of the inlet duct 240and the cover 256, and between the cover 256 and the inlet 250 of theoutlet duct 248, thereby minimizing the effect of the transitions on themovement of substance through solid feed pump 10. For instance, theillustrated cover 256 includes a curved entry section 262, a curved exitsection 264, and an intermediate straight section 266 (e.g., parallel indownstream direction) relative to the straight path portion 226. Incertain embodiments, the cover 256 may be adjustable to vary a volumebetween the cover 256 and the passing carriages 208. For example, thecover 256 may be moved toward or partially into the passing carriages208 to decrease a carrying capacity of each carriage 208, therebyreducing the flow rate of the pump 10. Likewise, the cover 256 may bemoved away from the passing carriages 208, while still maintaining aclosed volume between the cover 256 and the carriages 208, to increase acarrying capacity of each carriage 208 and, thus, increase the flow rateof the pump 10. As illustrated, the passing carriages 208 transport thesubstance from the inlet duct 240 in a carriage direction 268 along theintermediate straight section 266 to the outlet duct 248, which thenreceives the substance through the inlet 250 in an inlet direction 270.The outlet duct 248 then routes the substance through the closed wall254 and out through the outlet 252 in an outlet direction 272. Forexample, the outlet duct 248 may direct the substance, such as a solidfuel feedstock, into the gasifier 106 as shown in FIG. 1.

The curved entry section 262, curved exit section 264, and intermediatestraight section 266 of the cover 256 are configured to control the flowof substance between the inlet and outlet ducts 240 and 248. The curvedentry section 262 is configured to facilitate the flow of substance frominlet duct 240 into the moving carriages 208 in a somewhat convergingmanner, while the curved exit section 264 is configured to graduallyguide the substance from the carriages 208 into the outlet duct 248 in asomewhat diverging manner. In certain embodiments, the inlet duct 240and entry section 262 are configured to feed the substance intoreceptacles 210 in a somewhat diverging manner. Furthermore, in certainembodiments, the outlet duct 248 and exit section 264 may be configuredto discharge the substance in a somewhat converging manner. In otherembodiments, at least one of inlet duct 240 and entry section 262, andoutlet duct 248 and exit section 264 are configured to create a flowpath that is neither converging nor diverging. In some embodiments,inlet duct 240, entry section 262, outlet duct 248, and exit section 264may be configured to be any shape that facilitates operation of pump 10as described herein.

In the illustrated embodiment, the straight section 266 is parallel tothe bottom wall 212 of each passing carriage 208 forming a duct ofconstant cross-sectional area with carriages 208 downstream of inlet 234and upstream of outlet 236, wherein the bottom wall 212 and side walls216 are moving and the top wall or cover 256 serves as a stationaryguide surface. In certain embodiments, the cover 256 may be disposeddirectly along the open tops 214 of carriages 208. In certain otherembodiments, the cover 256 may extend partially below the open top 214of each carriage 208. In some embodiments, such as when pump 10 is usedwith certain compressible solids, the cover 256 may be shaped tosomewhat converge relative to the bottom walls 212 of the carriages 208along at least a portion of intermediate lockup zone 238. Furthermore,some embodiments of the cover 256 may first somewhat converge and thensomewhat diverge relative to the bottom walls 212 of the passingcarriages 208. In other embodiments, the cover 256 may have any shapethat facilitates the operation of pump 10 as provided herein.

Upon reaching the inlet 250 of the outlet duct 248, the substance ineach passing carriage 208 is guided into and through the outlet duct248. For instance, in the illustrated embodiment, the curved exitsection 264 of the cover 256 extends at least partially into the inlet250 of the outlet duct 248. In addition, the inlet 250 of the outletduct 248 may be disposed directly along the bottom wall 212 of eachpassing carriage 208. For example, the inlet 250 of the outlet duct 248may be angled upwardly in a downstream direction along the bottom wall212 of the passing carriages 208, thereby scooping up or scraping up thesubstance in each holding receptacle 210 of the passing carriages 208.Furthermore, at least one upstream edge of inlet 250 of outlet duct 248may be shaped to facilitate the pickup of substance from receptacles210, including but not limited to incorporating one or more knife-likeleading edges.

The outlet duct 248 may have a variety of geometries and orientations tofacilitate operation of the pump 10. In the illustrated embodiment, theinlet direction 270 of the substance entering the outlet duct 248 isoriented generally along the horizontal axis 14 and the carriagedirection 268. In other words, the inlet direction 270 is not abruptlyangled relative to the carriage direction 268 of the passing carriages208 moving along the upper straight path portion 226. For example, theinlet direction 270 may be at least initially parallel to the horizontalaxis 14 and the carriage direction 268, and then the inlet direction 270may gradually curve upward away from the horizontal axis 14. By furtherexample, an upstream duct portion 273 of the outlet duct 248 maygradually curve by an angle of less than approximately 5, 10, 15, 20,25, or 30 degrees relative to the horizontal axis 14 and the carriagedirection 268. In turn, the outlet duct 248 may change the direction ofthe substance from the upstream duct portion 273 to a downstream ductportion 274. For example, the downstream duct portion 274 may turn thesubstance in a downward direction, an upward direction, or a straighthorizontal direction. However, the outlet duct 248 may have a variety oforientations and geometries based on implementation-specific designconsiderations.

In certain embodiments, the orientation and geometry of the outlet duct248 may be configured to facilitate the feeding of the substance into adownstream system operating at a similar or a much higher pressure,e.g., only metering or both metering and pressurization. For example, inthe illustrated embodiment, outlet duct 248 is configured to feed thesubstance into a downstream system operating at higher pressure byincorporating an upward angle and turn through the outlet duct 248. Theupward angle and turn may help provide a back flow resistance thatsubstantially limits or eliminates the permeation or back flow ofdownstream high pressure fluid through the outlet duct, while stillenabling flow of the solid feedstock in the downstream direction. Theinlet zone 234 and lock-up zone 238 thus may operate at substantiallythe same pressure as the supply to pump 10, while feeding substance to ahigh pressure downstream system. Again, in certain embodiments, thegeometry of the outlet duct 248 may be designed for metering only, andthus the outlet duct 248 may be modified to significantly improve flowand reduce pressurization through the outlet duct 248. For instance, inone embodiment, the outlet duct 248 may be oriented parallel to thestraight path portion 226 (e.g., horizontal). In another embodiment, theoutlet duct 248 may be initially oriented substantially parallel to thestraight path portion 226 (e.g., horizontal), and then turn away fromthe straight path portion 226 (e.g., vertically downward). The outletduct 248 also may include a valve or pressure control mechanism, such asa flapper, to assist with startup of the pump 10 and/or to maintain aback pressure on the substance being discharged from the pump 10. Forexample, the pressure control mechanism may help lock up a substancebeing transported through the pump 10, thereby helping to achieve adesired flow rate through the pump 10.

In the illustrated embodiment, the partial overlapping in the transportsection 200 of the pump 10 occurs to the extent that the adjacentcarriages 208 may be considered to be fully engaged with one another,thereby forming a progressing rigid channel with fixed cover 256 totransport the substance through the transport section 200 of the pump10. However, with certain substances, the spacing between the matingsurfaces between carriages 208, cover 256, inlet duct 240, and outletduct 244 may not be sufficiently small to block all leakage of thesubstance into the casing of the segmented solid feed pump 10. In someembodiments, the casing of pump 10 may include a removable window tofacilitate the periodic removal of leaked substance from the casing ofpump 10. Furthermore, in some embodiments, the casing of pump 10 mayhave at least one discharge port to facilitate the removal of thesubstance from the casing of pump 10. In addition, in some embodiments,the leakage of the substance from transport section 200 into the casingof pump 10 during operation may be controlled by using seals between themating faces of the carriages 208, cover 256, inlet duct 240, and outletduct 244. For example, the seals may include, but are not limited to,brush seals, polymeric seals, graphite impregnated fiber or fabricseals, or ceramic seals. The seals may be designed to block leakage ofthe solid feedstock. However, as discussed below, the seals may or maynot block fluid (e.g., gas) leakage between the mating faces of thecarriages 208, cover 256, inlet duct 240, and outlet duct 244. In someembodiments, the pump 10 is calibrated or monitored to account for theleakage of substance in determining the net flow of substance throughpump 10.

In certain embodiments, the pump 10 includes pressure-tight sealsbetween the mating faces of carriages 208, cover 256, inlet duct 240,and/or outlet duct 244. The pressure-tight seals may be useful inapplications having an elevated pressure downstream from the pump 10(e.g., a higher pressure downstream system) or an elevated pressureupstream from the pump 10 (e.g., a higher pressure upstream system). Forexample, a pressure rise associated with feeding a substance to anelevated pressure downstream of the pump 10 may be taken across at leasta portion of the substance and associated pump 10 components withinlockup zone 234. By further example, a pressure drop associated withletting down the pressure of the substance from an elevated pressureupstream of the pump 10 may be taken across at least a portion of thesubstance contained within lockup zone 234. Additionally, in someembodiments, an inert gas may be injected upstream of the pressureletdown region to control leakage of a high pressure upstream fluid.

In the illustrated embodiment, the inlet duct 240 and the outlet duct248 may have constant or variable geometries between their respectiveinlets and outlets. For example, the illustrated inlet duct 240 has asomewhat converging geometry from the inlet 242 to the outlet 244. Incontrast, the outlet duct 248 has a somewhat diverging geometry from theinlet 250 to the outlet 252. The somewhat converging geometry from theinlet duct 240 may be configured to facilitate guiding the substanceinto the passing carriages 208. The somewhat diverging geometry of theoutlet duct 248 may be configured to control the pressurization, powerrequirements, and flow of the substance out of the pump 10. However, theoutlet duct 248 may have a variety of converging or diverging geometriesto control the flow and pressurization of the substance passing throughthe outlet duct 248.

The illustrated segmented solid feed pump 10 also may include acontroller 276, one or more drives 278 coupled to the controller 276,and one or more sensors 280 coupled to the controller 276. In certainembodiments, the drive 278 may include an electric motor, a combustionengine, a hydraulic drive, a pneumatic drive, or any suitable drivingmechanism. The drive 278 may be coupled to the track structure 224 orone or more of the carriages 208 depending on the particular embodiment.For example, in an embodiment having a moving track structure 224, thedrive 278 may be coupled to the track structure 224 to cause motionalong the closed-loop path 206. In an embodiment with a stationary trackstructure 224, the drive 278 may be coupled to one or more of thecarriages 208 to cause movement of the carriages 208 along theclosed-loop path 206. The one or more sensors 280 may include a carriagecounter, a weight sensor, a speed sensor, or any other suitable sensingmechanism to facilitate control of the segmented solid feed pump 10. Thecontroller 276 may be configured to control the torque and/or speed ofthe drive 278 based on input from the one or more sensors 280. Forexample, the controller 276 may increase or decrease the speed of thedrives 278 depending on the number of passing carriages 208 per time,the volume or weight of the substance in each carriage 208, or otherinputs. The controller 276 also may receive input from external sources,such as the feedstock preparation unit 104, the gasifier 106, or othercomponents of the IGCC system 100 as shown in FIG. 1. In someembodiments, the speed or volumetric control incorporates an adjustmentthat takes into account the volumetric filling efficiency of receptacles210, such as the effects of carriage speed and the physical propertiesof the substance being metered by solid feed pump 10. In furtherembodiments, the physical properties that may affect the volumetricfilling efficiency of the receptacles 210 are measured on-line and themeasured values of the properties are used for control. The controller276 also may control the position of the cover 256, thereby varying thevolume of a substance being delivered between the cover 256 and thepassing carriages 208.

FIG. 3 is a schematic side view of an embodiment of the segmented solidfeed pump 10 of FIG. 2, illustrating an alternative configurationoriented in a different vertical arrangement relative to the verticalaxis 16. In the illustrated embodiment, the segmented solid feed pump 10has the closed-loop path 206 oriented in a vertical plane relative tothe vertical axis 16, wherein the closed-loop path 206 is rotatedapproximately 90 degrees relative to the embodiment of FIG. 2. Inparticular, the illustrated closed-loop path 206 has the oppositestraight path portions 226 and 228 oriented parallel to the verticalaxis 16, while the opposite curved path portion 230 and 232 are disposedvertically one over the other. In this alternative vertical arrangement,the material transport section 200 is also rotated by approximately 90degrees along with the straight path portion 226.

In this embodiment, the inlet duct 240 receives a substance into theinlet 242 in a generally vertical inlet direction 258, and then deliversthe substance also in a generally vertical direction 260 into thepassing carriages 208. In turn, the substance carried by the holdingreceptacle 210 of each carriage 208 passes in the vertical carriagedirection 268 from the inlet duct 240 toward the outlet duct 248. Thecover 256 along the lock-up zone 238 is oriented along the vertical axis16, thereby guiding and holding the substance carried by each carriage208 from spilling out before reaching the outlet duct 248. Upon reachingthe outlet duct 248, the substance enters the inlet 250 of the outletduct 248 in a generally vertical inlet direction 270. As discussedabove, the inlet direction 270 may be at least initially parallel to thecarriage direction 268, which is parallel to the vertical axis 16 in theillustrated embodiment. However, the inlet direction 270 may be slightlyangled or gradually angled away from the carriage direction 268 and thevertical axis 16 from the inlet 250 through the upstream duct portion273.

In the illustrated embodiment, the outlet duct 248 has an intermediateduct portion 282 between the upstream duct portion 273 and thedownstream duct portion 274. In this intermediate duct portion 282, theoutlet duct 248 may turn by approximately 90 degrees or more relative tothe carriage direction 268 and the vertical axis 16. As a result, thedownstream duct portion 274 may be oriented along the horizontal axis14. However, in the illustrated embodiment, the downstream duct portion274 delivers the substance through the outlet 252 in an upwardly angledoutlet direction 272. For example, the outlet direction 272 may beangled by approximately 0, 10, 20, or 30, 40, or 50 degrees relative tothe horizontal axis 14. Accordingly, the turn in the intermediate ductportion 282 may facilitate pressurization of the substance to facilitatethe feeding or metering of the substance to a higher pressure systemdownstream of outlet duct 248. For example, the angle of the turn, theexpansion in the turn, and the general geometry of the outlet duct 248may work in concert with the substance to pressurize the substance,while maintaining the associated power to transport the substancethrough outlet duct 248 at a desired level.

In some embodiments, the outlet duct 248 may deliver the substance in avertically downward direction or an angled downward direction relativeto the vertical axis 16. In such an embodiment, the inlet duct 240 andthe outlet duct 248 are generally oriented in the same direction, i.e.,downward. In contrast to an embodiment having an upward turn in theintermediate duct portion 282, an embodiment directing the outlet duct248 in a downward direction may provide for metering without a pressureincrease in the substance passing through the outlet duct 248. In otherwords, a downwardly directed outlet duct 248 may provide either apressure letdown or no pressure change, while still enabling metering ofthe substance in the segmented solid feed pump 10.

In other embodiments, the flow direction may be reversed in thesegmented solid feed pump 10 shown in FIG. 3. For example, theillustrated duct 248 may function as an inlet duct, while theillustrated duct 240 may function as an outlet duct. Again, theorientation and geometry of these ducts 240 and 248 may vary from oneimplementation to another. For example, the ducts 240 and 248 may beangled upward, downward, or generally horizontal. Furthermore, the ducts240 and 248 may have generally parallel orientations, perpendicularorientations, or any suitable angle relative to one another. In oneembodiment, the duct 248 may be angled in an upward direction to receivea substance, while the duct 240 may be angled upward, horizontal, ordownward. Again, a variety of configurations and geometries are withinthe scope of the disclosed embodiments.

FIG. 4 is a schematic top view of an embodiment of the segmented solidfeed pump 10 oriented in a horizontal plane. However, in certainembodiments, the pump 10 of FIG. 4 may be oriented in a vertical planeor an angled plane between horizontal and vertical planes. Asillustrated, the carriage loop 202 and the closed-loop path 206 areparallel to the horizontal axes 12 and 14, such that the open top 214 ofeach carriage 208 is facing vertically upward out of the page in thevertical direction 16. Thus, in contrast to the embodiments of FIGS. 2and 3, the orientation of the open top 214 does not change along thecarriage loop 202, but rather it is constantly facing upward along theentire carriage loop 202. The carriage loop 202 may be coupled to (orguide) each carriage 202 along the bottom wall 212 or one of theopposite sides walls 216. Accordingly, the front and rear couplings 218and 222 of each carriage 208 may be modified to maintain a suitableoverlap between adjacent carriages 208 through transport section 200,while also enabling flexible movement of the carriages 208 along theopposite curved path portions 230 and 232 of the close loop path 206.

Furthermore, a pair of the material transport sections 200 is verticallystacked over the carriage loop 202 separately along the straight pathportion 226 and the straight path portion 228. In some embodiments, thepump 10 may include any number of material transport sections 200 (e.g.,1 to 10) disposed along the carriage loop 202. For example, the pump 10may include 2, 3, 4, or more material transport sections 200. As aresult, the illustrated embodiment of the pump 10 includes two separatematerial transport sections 200 disposed opposite from one another alongthe single closed-loop path 206. For example, each material transportsection 200 may be disposed along one of the respective straight pathportions 226 or 228. Thus, the pump 10 of FIG. 4 has a greater capacitythan the pumps 10 of FIGS. 2 and 3, because the pump 10 of FIG. 4 hastwo separate inlet ducts 240 and two separate outlet ducts 248. In otherwords, the two material transport sections 200 substantially increasethe capacity of the pump 10 for a given carriage loop 202.

In certain embodiments, the two material transport sections 200 may beoperated alone or in combination with one another. For example, thecontroller 276 may receive feedback from sensors 280 disposed at eachinlet or metering zone 234, feedback from external sensors indicating ademand for a substance, or feedback from external sensors indicating asupply of a substance. For example, the controller 276 may receivemetering feedback from the sensors 280 or external control signals fromthe feedstock preparation unit 104, the gasifier 106, or other portionsof the IGCC system 100. Depending on the desired flow of the substancethrough the segmented solid feed pump 10, the controller 276 may adjustthe speed via the drive 278, or selectively engage or disengage one orboth of the metering zones 234. For example, the controller 276 mayblock flow of the substance into one of the metering zones 234, therebydisabling that particular material transport section 200. In thismanner, the segmented solid feed pump 10 has a greater control onthroughput of the substance to the gasifier 106 (or another downstreamsystem).

FIG. 5 is a schematic side view of an embodiment of the segmented solidfeed pump 10 as illustrated in FIG. 4. As discussed above, theillustrated pump 10 may have a horizontal arrangement, a verticalarrangement, or an arrangement between horizontal and verticalarrangements in various embodiments. However, as illustrated, the trackstructure 224 is oriented parallel to the horizontal plane through thehorizontal axes 12 and 14, such that the carriage loop 202 and thematerial transport section 200 are disposed vertically above the trackstructure 224. For example, the pump segments 204 may move along theclosed-loop path 206 in a manner curving into the page on the far leftand curving out of the page on the far right. In the illustratedembodiment, each carriage 208 has one or more track followers or wheels222 disposed between the bottom wall 212 and the track structure 224. Inaddition, the open top 214 of each carriage 208 is substantially orentirely covered by the contoured guide plate or cover 256 between theinlet duct 240 and the outlet duct 248.

In the illustrated embodiment, inlet duct 240 has a configurationsimilar to the embodiment of FIG. 2, while the outlet duct 248 has aconfiguration different than the embodiment of FIG. 2. For example, theoutlet duct 248 intersects with the moving carriages 208 in asubstantially parallel orientation along the horizontal axis 14 andrises vertically gradually and with relatively constant cross-sectionalarea. The gradual interface angle between the duct 248 and the movingcarriages 208 may substantially improve the performance of the segmentedsolid feed pump 10. For example, the gradual interface angle may reducethe possibility of jamming or clogging of the substance beingtransported by the pump 10, while also reducing the power of the drive278 sufficient to move the carriages 208 and substance along thematerial transport section 200. In other words, the gradual interfaceangle may reduce the resistance to movement of the pump segments 204along the closed-loop path 206. As illustrated in FIG. 5, the outletduct 248 may turn approximately 60 to 120 degrees, 70 to 110 degrees, 80to 100 degrees, or about 90 degrees. However, the inlet and outlet ducts240 and 248 may have any angle, orientation, and shape in variousembodiments of the pump 10.

FIGS. 6, 7, 8, 9, and 10 are different views of an embodiment of a pumpsegment 204 that may be used in the segmented solid feed pump 10 asillustrated in FIGS. 1-5. FIG. 6 is a side view of three pump segments204 of the carriage loop 202, illustrating an overlappinginterconnection of adjacent carriages 208 via the front coupling 218 andthe rear coupling 220. As illustrated, each carriage 208 has the frontcoupling 218 mated with an adjacent rear coupling 220, while eachcarriage 208 also has the rear coupling 220 mated with an adjacent frontcoupling 218. The overlapping interconnection of these front and rearcouplings 218 and 220 substantially captures a substance across theadjacent carriages 208. For example, the overlap between the front andrear couplings 218 and 220 may provide overlap along the bottom wall 212and the opposite side walls 216 from one carriage to another.Furthermore, in certain embodiments, each pump segment 204 mayincorporate at least one seal along at least one mating surface toreduce leakage of the substance and other process fluids, such as butnot limited to high pressure gas.

FIG. 7 is a side view of an embodiment of the pump segment 204 asillustrated in FIGS. 1-6. As illustrated, the pump segment 204 has thefront and rear couplings 218 and 220 disposed on opposite ends of thecarriage 208. In the illustrated embodiment, the front coupling 218 hasa female portion 300 recessed into the bottom wall 212 and the oppositeside walls 216. The rear coupling 220 has a male portion 302 extendingoutwardly from the bottom wall 212 and the opposite side walls 216. Incertain embodiments, each carriage 208 may have a reversed configurationwith the female portion 300 disposed at the rear coupling 220 and themale portion 302 disposed at the front coupling 218. In eitherarrangement, the female portion 300 and the male portion 302 havesubstantially similar or identical dimensions configured to fit with oneanother between adjacent carriages 208. For example, the female portion300 may have a vertical depth 304, a horizontal depth 306, and avertical offset 308 relative to a bottom surface 310 of the bottom wall212. Likewise, the male portion 302 may have a vertical depth 312, ahorizontal depth 314, and a vertical offset 316 relative to the bottomsurface 310. These dimensions and shapes of the portions 300 and 302 maybe configured to facilitate the movement between and alignment ofadjacent carriages 208, while providing substantial overlap betweenadjacent front and rear couplings 218 and 220.

FIG. 8 is a top view of an embodiment of the pump segment 204 asillustrated in FIGS. 1-7. As illustrated, the female portion 300 isrecessed into the opposite side walls 216, while the male portion 302protrudes outwardly from the opposite side walls 216. In particularly,the illustrated female portion 300 is recessed into both of the oppositeside walls 216 by a lateral offset 318 relative to an interior sidesurface 320 of the sidewalls 216. In contrast, the male portion 302protrudes from both of the opposite sidewalls 216 with a lateralthickness 322 flush with the interior side surfaces 320. In theillustrated embodiment, the dimensions 318 and 322 of the female andmale portions 300 and 302 are substantially equivalent, and aresubstantially less than a thickness 324 of the opposite side walls 216.The engagement of male and female portions 300 and 302 between adjacentcarriages 208 provides a substantial overlap along both sidewalls 216and the bottom wall 212.

FIG. 9 is a cross-sectional end view of the pump segment 204 taken alongline 9-9 of FIG. 7. In particular, FIG. 9 illustrates a cross-section ofthe female portion 300 of the front coupling 218 of the carriage 208. Inthe illustrated embodiment, the female portion 300 has a U-shaped recess326 extending into the bottom wall 212 and the opposite side walls 216.However, the recess 326 may have a variety of shapes and configurationsin other embodiments of the pump segment 204.

FIG. 10 is a cross-sectional end view of the pump segment 204 takenalong line 10-10 of FIG. 7. In particular, FIG. 10 illustrates across-section of the male portion 302 of the rear coupling 220 of thecarriage 208. As illustrated, the male portion 302 has a U-shapedprotrusion 328 extending outwardly from the bottom wall 212 and theopposite side walls 216. As appreciated, the U-shaped protrusion 328 isconfigured to mate with the U-shaped recess 326 of an adjacent carriage208, thereby providing overlap along the bottom walls 212 and theopposite side walls 216 of the adjacent carriages 208.

FIGS. 11, 12, 13 and 14 are cross-sections taken through line 11-11,line 12-12, line 13-13, and 14-14 of FIG. 5. These figures illustratethe transition from the lock-up zone 238 into and through thepressurization zone 236. In particular, FIG. 11 is a cross-sectionalview in the lock-up zone 238, illustrating the cover 256 disposed overone of the carriages 208. As illustrated, the cover 256 extends over theopen top 214 and around the opposite side walls 216 of the carriage 208.In this manner, the cover 256 and the carriage 208 completely enclosethe holding receptacle 210 inside the carriage 208. In the illustratedembodiment, the cover 256 has a downwardly facing U-shape, while thecarriage 208 has an upwardly facing U-shape. These opposite U-shapesoverlap with one another to block any leakage of a substance residing inthe holding receptacle 210. In certain embodiments, seals areincorporated in the carriages 208, the cover 256, or both, to facilitatethe control of leakage.

FIG. 12 is a cross-sectional view of the pressurization zone 236 of thematerial transport section 200, illustrating the outlet duct 248interfacing with one of the carriages 208. In particular, the outletduct 248 includes an upper duct portion 340 and a lower duct portion 342to capture a substance being delivered by the holding receptacle 210 ofthe carriage 208. In the illustrated embodiment, the upper duct portion340 extends over the open top 214 and around the opposite side walls 216of the carriage 208, while the lower duct portion 342 is disposed insidethe carriage 208 along the bottom wall 212. Similarly, although notillustrated in FIG. 12, the inlet duct 248 may have upper and lower ductportions, wherein the lower duct portion extends to a bottom of thecarriages 208 to guide flow of a substance into the carriages 208 whileblocking any backflow of the substance. As illustrated in FIG. 12, theupper duct portion 340 has a downwardly facing U-shape, while thecarriage 208 has an upwardly facing U-shape. These opposite U-shapesoverlap with one another to block any leakage of a substance residing inthe holding receptacle 210. In addition, the lower duct portion 342 mayinitially interface with the bottom wall 212 in close proximity with abottom interior surface 344. In other words, the lower duct portion 342may have a tight clearance with the bottom interior surface 344 of thecarriage 208. In this manner, the lower duct portion 342 is configuredto guide the substance within the holding receptacle 210 in an upwarddirection away from the bottom interior surface 344, thereby channelingthe substance through the outlet duct 248. In certain embodiments, theleading edge of lower duct portion 342 has an acute angle to ease thetransition of the solid feedstock from the carriage 208 into outlet duct248. For instance, the leading edge of lower duct portion 342 may be anacute angle between approximately 0 and 30 degrees, such as an anglebetween approximately 5 and 20 degrees. In some embodiments, one or moreseals are disposed between lower duct portion 342 and carriage 208.Furthermore, some embodiments include one or more seals between carriage208 and both upper duct portion 340 and lower duct portion 342.

FIG. 13 is a cross-sectional view of the pressurization zone 236 takenalong line 13-13 of FIG. 5, further illustrating the transition of theoutlet duct 248 downstream of the position shown in FIG. 12. Asillustrated, the lower duct portion 342 of the outlet duct 248 issubstantially offset from the bottom interior surface 344, as indictedby vertical offset 346. Likewise, the upper duct portion 340 of theoutlet duct 248 is vertically expanded relative to the lower ductportion 342, as indicted by vertical offset 348. Thus, the upper andlower duct portions 340 and 342 gradually raise the contents from theholding receptacles 210 of the passing carriages 208 upwardly away fromthe carriage loop 202, while simultaneously expanding the verticalheight of the outlet duct 248. In some embodiments, the outlet duct 248may maintain rather than expand the vertical offset 348 in thedownstream direction. In other embodiments, the outlet duct 248 maycontract the vertical offset 348 in the downstream direction.

FIG. 14 is a cross-sectional view of outlet and pressurization zone 236taken along line 14-14 of FIG. 5, illustrating the transition of theoutlet duct 248 downstream of the position shown in FIG. 13. Asillustrated, the upper duct portion 340 and lower duct portion 342 havemerged into a single seamless duct. The seamless duct creates a smoothregion within outlet duct 248, which facilitates flow of the substancethrough the duct 248 toward the downstream process.

As generally illustrated by FIGS. 5, 11, 12, 13 and 14, the illustratedpump 10 transfers a substance into and through the lock-up zone 238 andthe outlet or pressurization zone 236 in a manner that meters andpressurizes the substance. In particular, FIG. 5 illustrates an upwardturn in the outlet duct 248, and FIGS. 12 and 13 illustrate a raisingbottom (e.g., lower duct portion 342), which facilitates the transitionof the substance from the carriages 208 into outlet duct 248. The outletduct 248 also may enable pressurization of the substance as thesubstance passes through the outlet duct 248. For example, carriages 208lock up the substance (e.g., coal) along the lock-up zone 238 betweenthe inlet and outlet ducts 240 and 248, thereby forcing the substanceagainst and into the outlet duct 248. The outlet duct 248 then createspressure in the substance in the sealed duct portion of outlet duct 248.In some embodiments, the outlet duct 248 may not include an upward turnwith a raising bottom (e.g., lower duct portion 342), and may notpressurize the substance. Instead, the outlet duct 248 may have astraight outlet path that subsequently turns downward. However, theoutlet duct 248 may have a variety of geometries and configurations invarious embodiments. Furthermore, certain embodiments of the outlet duct248 may include or exclude a valve configured to control a back pressureand/or maintain a pressure.

FIG. 15 is a partial schematic side view of an embodiment of thesegmented solid feed pump 10 as illustrated in FIGS. 1-14, illustratinga movable bottom wall 212 of the carriage 208. In certain embodiments,the movable bottom wall 212 may provide a more smooth transition of thesubstance from the carriages 208 into the outlet duct 248. Asillustrated, each carriage 208 includes a movable bottom wall 212 havinga carriage joint 360 coupled to the carriage 208 and a track joint 362disposed along a guide track 364. For example, the joints 360 and 362may include one or more pins configured to enable rotation of themovable bottom wall 212 depending on the position along the closed-looppath 206. The guide track 364 may include a pair of opposite channelspositioned about opposite sides of the carriages 208, such that oppositetrack joints 362 protrude from the carriages 208 into the guide track364. Likewise, the carriage joint 360 may include one or more pinsdisposed in channels located in the opposite side walls 216 of eachrespective carriage 208.

As the carriages 208 move in the carriage direction 268 along theclosed-loop path 206, the guide track 364 changes positions, therebyguiding the track joint 362 toward or away from the respective carriage208. In this manner, the interface between the track joint 362 and theguide track 364 causes rotation of the movable bottom wall 216 toimprove the interface with the material transport section 200. Forexample, as illustrated, the movable bottom walls 212 may remaingenerally horizontal along the metering zone 234 and the lock-up zone238 below the inlet duct 240 and the cover 256. Upon reaching the outletduct 248 of the pressurization zone 236, the guide track 364 may causethe movable bottom wall 212 to gradually pivot or rotate in a downwarddirection to create a tapered interface 366 between the movable bottomwalls 212 and the lower duct portion 342 of the outlet duct 248. Forexample, the carriage joint 360 may facilitate a downward and slightbackward movement of bottom walls 212. As a result of this movement, thebottom wall 212 of each carriage 208 is able to skim across the bottomleading edge of the lower duct portion 342 without opening gaps betweenadjacent bottom walls 212, e.g., due to the rotation until after themating joint 360 between two adjacent carriages 208 moves at least anoffset distance past the leading edge of lower duct portion 342. Forexample, the offset distance may include, but is not limited to, 1 to 5centimeters past the leading edge of lower duct portion 342. Therotation of the bottom walls 212 also may vary across differentimplementations of the pump 10. For example, an angle 368 between themovable bottom wall 212 and the lower duct portion 342 may range betweenapproximately 0 to 20 degrees. In certain embodiments, the angle 368 maybe less than approximately 5, 10, 15, 20, 25, or 30 degrees. The taperedinterface 366 may substantially improve the transition from thecarriages 208 into the outlet duct 248.

FIG. 16 is a partial schematic side view of an embodiment of thesegmented solid feed pump 10 as illustrated in FIGS. 1-15, illustratingcarriages 208 with movable bottom walls 212. In the illustratedembodiment, each bottom wall 212 is coupled to a guide track 380 via apivot arm 382. For example, the curvature of the guide track 380 maycontrol the rotational orientation of the pivot arm 382 and theremovable bottom wall 212 along the closed-loop path 206. In certainembodiments, the guide track 380 may include a belt, a chain, or a guidechannel mating with pins on each pivot arm 382. Similar to theembodiment of FIG. 15, the guide track 380 and pivot arms 382 areconfigured to position the movable bottom wall 212 in a generallyhorizontal position along the metering zone 234 and the lock-up zone238, while gradually pivoting the movable bottom wall 212 in thevicinity of the pressurization zone 236. In other words, uponapproaching the outlet duct 248, the guide track 380 may changedirections or positions relative to the carriage 208, thereby causingthe pivot arms 382 to rotate the bottom walls 212 to create a taperedinterface 386 between the bottom walls 212 and the lower duct portion342 of the outlet duct 248. Again, an angle 388 between the bottom wall212 and the lower duct portion 342 may range approximately 0 to 20degrees. For example, the angle 388 may be less than approximately 5,10, 15, 20, 25, or 30 degrees. Furthermore, the leading edge of eachbottom wall 212 may include a short extension 383 that extends under thepreceding bottom wall 212 to minimize leakage at the interface betweenadjacent carriages 208. For example, the extensions 383 may blockleakage between adjacent bottom walls 212 as the carriages 208 rotate inthe vicinity of the lower duct portion 342, e.g., during the approachand passing of the bottom walls 212 relative to the leading edge of thelower duct portion 342.

FIG. 17 is a partial schematic side view of an embodiment of thesegmented solid feed pump 10 as illustrated in FIGS. 1-16, illustratingcarriages 208 with movable bottom walls 212. In the illustratedembodiment, each carriage 208 is coupled to a first guide track 400 anda second guide track 402, which are independent and different from oneanother. More specifically, the guide track 400 couples to the oppositeside walls 216 of each carriage 208, while the guide track 402independently couples to the bottom wall 212 of each carriage 208. As aresult, the opposite side walls 216 follow a different route than thebottom walls 212 according to the differences between the first andsecond guide tracks 400 and 402.

In the illustrated embodiment, the guide rack 402 supporting the bottomwalls 212 diverges from the guide track 400 supporting the opposite sidewalls 216 as the carriages 208 approach the outlet duct 248, asindicated by arrows 268. In this manner, the guide track 402 graduallymoves the bottom walls 212 in a downward direction 404 to facilitate asmooth interface between the bottom walls 212 and the lower duct portion342 of the outlet duct 248. As illustrated, each bottom wall 212 has arectangular shape with a tapered top surface 406. The tapered topsurface 406 has a negative angle 408 relative to the direction 268toward the outlet duct 248. For example, the angle 408 may beapproximately 5 to 45 degrees. As each bottom wall 212 approaches thelower duct portion 342, the tapered top surface 406 slides along atapered bottom surface 410 of the lower duct portion 342. For example,the tapered bottom surface 410 may be angled similar to the angle 408 ofthe tapered top surface 406 to provide a smooth transition with aminimal clearance. The matched angles of tapered surfaces 406 and 410may reduce the possibility of leakage of the pumped substance, therebyreducing waste.

As illustrated, each bottom wall 212 includes a shaft 412 and a guidewheel 414. The shaft 412 extends through a shaft guide 416 coupled to alinkage 418, which is coupled to adjacent linkages 418 via pivot joints420. The linkages 418 and pivot joints 420 are coupled to the oppositeside walls 216 of each carriage 208, and follow the guide track 400 asindicated by arrows 422. For example, each carriage 208 may form aU-shaped structure defined by the opposite side walls 216 and thelinkage 418. The guide wheel 412 is captured in a slot 424 betweenopposite rails 426, such that the guide wheel 412 slides along the guidetrack 402 as indicated by arrows 428. In certain embodiments, the shaftguide 416 may include a hollow tube configured to enable upward anddownward movement of the shaft 412, thereby allowing upward and downwardmovement of the bottom wall 212 according to the position of the wheel414 along the guide track 402. As noted above, the guide track 402diverges from the guide track 400 in the region approaching the outletduct 248. As illustrated, the guide track 402 has an angle 430 away fromthe guide track 400. In certain embodiments, the angle 430 may besubstantially the same as the angle 408 of the tapered top surface 406of each bottom wall 212 and the tapered bottom surface 410 of the lowerduct portion 342. In this manner, the substantially matched angles mayimprove the transition of the bottom walls 212 to the lower duct portion342, while substantially preventing any leakage between adjacent bottomwalls 212 and the lower duct portion 342.

FIG. 18 is a schematic side view of an embodiment of the segmented solidfeed pump 10, illustrating the independent guide tracks 400 and 402 ofFIG. 16. In the illustrated embodiment, the segmented solid feed pump 10includes a pair of opposite material transport section 200 disposedalong the carriage loop 202, wherein the carriage loop 202 is defined bythe independent guide tracks 400 and 402. In particular, as discussedabove with reference to FIG. 17, the guide track 400 is configured toguide movement of the opposite side walls 216 and the linkage 418 ofeach carriage 208, while the guide track 402 is configured to guidemovement of the bottom wall 212 of each carriage 208.

The illustrated guide track 402 diverges from the guide track 400 infour locations corresponding to the inlet duct 240 and the outlet duct248 of each material transport section 200. Accordingly, the guide track402 includes a parallel path 450 along each material transport section200 between the inlet and outlet ducts 240 and 248, while the guidetrack 402 includes non-parallel paths (e.g., diverging paths 452 andconverging paths 454) in the transition region of the inlet and outletducts 240 and 248. For example, as each carriage 208 approaches theoutlet duct 248, the diverging path 452 may decrease the height of thebottom wall 212. As each carriage 208 approaches the inlet duct 240, theconverging path 454 may increase the height of the bottom wall 212.These variations in height in the bottom wall 212, along with thetapered top surfaces 406, substantially improve the transition of thecarriages 208 relative to the inlet and outlet ducts 240 and 248, whilealso reducing the possibility of leakage. As appreciated, the first andsecond guide paths 400 and 402 may have a variety of alternativeconfigurations in other embodiments.

FIG. 19 is a schematic side view of an embodiment of the segmented solidfeed pump 10, illustrating the material transport section 200 disposedalong an inwardly curved portion 460 of the closed-loop path 206. In theillustrated embodiment, the inlet duct 240 and the outlet duct 248 aredisposed at transitions 462 and 464 between the inwardly curved portion460 and outwardly curved portions 466 and 468 of the closed-loop path206. Furthermore, the inlet and outlet ducts 240 and 248 may be orientedperpendicular to the plane of the closed-loop path 206. In addition, theillustrated embodiment orients the open top 214 of each carriage 208outwardly toward the cover 256, which has an inwardly curved shapecorresponding to the inwardly curved portion 460 of the closed-loop path206. Again, the closed-loop path 206 may have any suitable geometry orconfiguration in various embodiments of the pump 10.

In certain embodiments, the pump 10 may be configured with cleaningequipment to facilitate removal and collection of accumulated substancefrom the surfaces of the segments, internal components, and otherportions of pump 10 during operation of pump 10 or while the pump 10 isoffline (i.e., shutdown). For example, the cleaning equipment mayinclude, but it not limited to, brushes, automatic blowers, and dustcollectors. In some embodiments, the pump 10 may continuously and/orautomatically perform cleaning operations (e.g., removal and collection)based on at least one sensor or at least one timer.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1. A system, comprising: a segmented solid feed pump, comprising: aclosed-loop path; and a plurality of pump segments coupled together inseries along the closed-loop path, wherein each pump segment comprises aholding receptacle, and the plurality of pump segments move along theclosed-loop path.
 2. The system of claim 1, wherein each pump segmentcomprises a carriage having a bottom wall, opposite side walls, and anopen top defining the holding receptacle.
 3. The system of claim 2,wherein adjacent pump segments comprise an overlapping connection alongthe opposite side walls and the bottom wall.
 4. The system of claim 3,wherein the overlapping connection comprises a U-shaped interface. 5.The system of claim 2, wherein the bottom wall of each pump segmentcomprises a movable portion configured to move relative to the oppositeside walls.
 6. The system of claim 5, wherein the movable portioncomprises a rotatable portion configured to rotate relative to theopposite side walls.
 7. The system of claim 2, comprising a guide trackcoupled to the bottom wall of each pump segment.
 8. The system of claim1, wherein the segmented solid feed pump comprises a first transportsection disposed along a first portion of the closed-loop path, whereinthe first transport section comprises a first inlet duct, a first outletduct, and a first guide extending between the first inlet duct and thefirst outlet duct.
 9. The system of claim 8, wherein the segmented solidfeed pump comprises a second transport section disposed along a secondportion of the closed-loop path, wherein the second transport sectioncomprises a second inlet duct, a second outlet duct, and a second guideextending between the second inlet duct and the second outlet duct,wherein the first and second portions are opposite straight portions ofthe closed-loop path.
 10. The system of claim 8, wherein the firstoutlet duct comprises a lower duct portion extending into the holdingreceptacle of each passing pump segment at an angle relative to theclosed-loop path, and the angle is at least less than approximately 45degrees.
 11. The system of claim 8, wherein the first outlet ductcomprises an upper duct portion and a lower duct portion, the upper ductportion covers the holding receptacle of each pump segment moving by thefirst outlet duct, and the lower duct portion extends into the holdingreceptacle toward a bottom wall of each pump segment moving by the firstoutlet duct.
 12. A system, comprising: a segmented solid feed pump,comprising: a closed-loop path; a plurality of pump segments coupledtogether in series along the closed-loop path, wherein the plurality ofpump segments move along the closed-loop path; and a first materialtransport section disposed in a first fixed position along a firstportion of the closed-loop path, wherein the first material transportsection comprises a first inlet duct, a first outlet duct, and a firstguide extending between the first inlet duct and the first outlet duct.13. The system of claim 12, wherein each pump segment comprises acarriage having a bottom wall, opposite side walls, and an open topdefining a holding receptacle, wherein adjacent pump segments comprisean overlapping connection along the opposite side walls and the bottomwall.
 14. The system of claim 12, wherein each pump segment comprises amovable wall portion configured to move relative to the pump segment.15. The system of claim 14, wherein the movable wall portion comprises arotatable wall portion configured to rotate relative to the pumpsegment.
 16. The system of claim 12, wherein the segmented solid feedpump comprises a second transport section disposed in a second fixedposition along a second portion of the closed-loop path, wherein thesecond transport section comprises a second inlet duct, a second outletduct, and a second guide extending between the second inlet duct and thesecond outlet duct.
 17. A system, comprising: a segmented solid feedpump, comprising: a closed-loop path; and a plurality of pump segmentscoupled together in series along the closed-loop path, wherein theplurality of pump segments move along the closed-loop path, wherein eachpump segment comprises opposite side walls, an open top, and a movablebottom wall.
 18. The system of claim 17, comprising a guide trackindependent from the closed-loop path, wherein the movable bottom wallof each pump segment has a segment orientation or a segment positionrelative to each pump segment that varies based on a position along theguide track.
 19. The system of claim 17, comprising a material transportsection disposed in a fixed position along a portion of the closed-looppath, wherein the material transport section comprises an inlet duct, anoutlet duct, and a guide extending between the inlet duct and the outletduct.
 20. The system of claim 19, wherein the movable bottom wall ofeach pump segment has a first orientation generally parallel to theclosed-loop path and a second orientation generally tilted relative tothe closed-loop path, the movable bottom wall of each pump segment hasthe first orientation while moving along the inlet duct and the guide,and the movable bottom wall of each pump segment has the secondorientation while moving along the outlet duct.